Defragment !!!!!!!!only 10% Win98 2nd Edition

hi guys

I have big problem
I have Win98 2nd Edition and it's new
I bought it one month only

and look to what happend when I do the Defragment
in D and E
it's okay
but in C
it's only reach 10% and then return to 0
Why!!
I stop working ScreenSaver
and !!!!!!
nothing change!!!
help me plz
but don't say
"Format"